Abstract: The injection of an ammonium sulfite or bisulfite solution increases the permeability of an uranium ore bed that has suffered permeability losses during the in-situ mining of uranium with an alkaline leach solution containing a peroxide or dissolved oxygen oxidant. Such an injection recovers much of the lost formation permeability, thus decreasing costs and effort required to put needed restoration solutions or further leach solutions through the ore bed. In addition, uranium contamination of the ground water normally occurring after cessation of leaching is significantly lowered by such injection.

Abstract: Aluminum nitrate solutions are subjected to hydrolysis at elevated temperature and pressure, with the pressure being kept relatively low by continual bleeding of reactant gases from the reaction vessel. The resultant product is a noncrystalline alumina that may be readily converted to crystalline alumina by roasting.In addition, the discharged reactant gases are employed for leaching of clay to provide aluminum nitrate feed solution.

Abstract: To recover chromium from scrap such as superalloy scrap, the feedstock is melted, subjected to controlled oxidation to oxidize and slag off reactive metals, then subjected to sulfidation and slow cooling to produce a coarse-grained solid wherein the bulk of the chromium is present in a phase consisting predominantly of a chromium sulfide.

Abstract: AlCl.sub.3.6H.sub.2 O is decomposed at a temperature above about 700.degree. C. in the presence of hydrogen to form an alumina product having a very low residual chlorine content.

Abstract: There is disclosed a process for recovering nickel (II), copper (II) and cobalt (II) from an ammoniacal-ammonium sulfate leach liquor. This process includes the step of adjusting the pH of the leach liquor prior to co-extracting the nickel and the copper values. Cobalt is recovered as cobalt (II) by reduction of cobalt (III) to cobalt (II) following by an extraction step.

Abstract: Percolation leaching of gold or silver ores, tailings or wastes is accomplished by a process comprising initial agglomeration of fines in the feed by means of a binding agent and water, followed by aging and, subsequently, leaching to recover gold or silver values.

Abstract: Exhausted Cr.sup.+6 oxidizing solutions containing Cu.sup.+2 values are electrolyzed by placing an exhausted Cr.sup.+6 etching or oxidizing solution containing copper ion and Cr.sup.+3 ions in an electrolytic cell containing at least one pair of carbon particle electrodes, and forcefully flowing the exhausted solution through the electrodes and simultaneously impressing a direct current across the electrodes such that at the cathode divalent copper is reduced to copper metal and Cr.sup.+6 values are reduced to trivalent chromium and at the anode water is oxidized to oxygen.

Abstract: Highly active catalysts, suitable for use in hydrogenation and other reactions, are prepared from an alloy of one or more of the Group VIII transition metals with yttrium or a rare earth metal. The alloy is ground to the desired particle size and is thereafter reacted with a gas containing carbon monoxide and hydrogen to form an intimate physical admixture of the Group VIII metal or its corresponding carbide with the oxide of yttrium or the rare earth metal.

Abstract: A cement composition comprising a high calcium-content fly ash and calcium sulfate, and mortar and concrete compositions containing the cement.

Abstract: A rapid, energy efficient, low cost, nonhazardous method for the selective removal of mercury from mercury-containing metal cyanide solutions, particularly the cyanide solutions resulting from the cyanidation of gold ore and the like, wherein a reactive sulfide is admixed with the solution for a time sufficient to form an insoluble mercuric sulfide precipitate. The mercuric sulfide precipitate is then separated from the metal cyanide solution by filtration or other conventional means.

Abstract: A low cost, effective method for removing heavy metal ions from aqueous solution which utilizes a porous, high surface-to-weight ratio siliceous adsorbent comprises the steps of activating the siliceous adsorbent, which is preferably a kaolin clay leach residue, with a basic salt of an alkali metal to incorporate alkali ions into the siliceous adsorbent and contacting the heavy metal ion-containing solution with the activated adsorbent whereby the heavy metal ions exchange with the alkali ions to remove the heavy metal ions from solution. The heavy metal ion loaded adsorbent may be stripped for subsequent reuse or, alternatively, utilized for flux in base metal smelting and the like.

Abstract: Percolation leaching of gold or silver ores, tailings or wastes is accomplished by a process comprising initial agglomeration of fines in the feed by means of a binding agent and cyanide solution, followed by aging and, subsequently, leaching to recover gold or silver values.

Abstract: An electrolytic stripping cell is provided which is particularly adapted for use in processing shredded, silver brazed, stainless steel honeycomb scrap. The cell comprises a mesh anode basket which rotates within a cathode cylinder to provide partial stirring of the cell electrolyte. The anode basket includes a central hollow shaft having holes therein through which the electrolyte continually circulates. The basket includes wiper blades for dislodging silver dentrites which grow between the anode and cathode and which, as they fall, are collected in a mesh basket located at the bottom of the cell housing.

Abstract: There is disclosed, in a process for separating zirconium and hafnium, an improvement for the removal of sodium sulfate from a sulfate-containing sodium chloride solution. This improvement includes adding a water-miscible organic precipitant such as methanol, ethanol or acetone to the sulfate-containing sodium chloride solution. The precipitant is added in an amount sufficient to cause the removal of sulfate as sodium sulfate. The organic precipitant is removed and the substantially sulfate ion free sodium chloride solution is recycled. Also provided is a process for the recovery of sodium sulfate having a purity greater than 99.9%.

Abstract: An 8-hydroxyquinoline-resorcinol-formaldehyde ion exchange resin, in bead form, is employed for sorption of tungsten from alkaline solutions such as brines.

Abstract: Spent asphaltic concrete is recycled by crushing, heating and admixing with sulfur at elevated temperature.

Abstract: A method for producing substantially pure alumina from kaolin clay by removing in a soluble form impurities which contaminate the alumina while the aluminum is maintained in an insoluble form. This is accomplished by leaching calcined kaolin clay with at least 36 weight percent hydrochloric acid to dissolve the impurities and convert the aluminum to insoluble aluminum chloride and maintaining the hydrochloric acid concentration in the leach liquor at at least 36 weight percent by the injection of hydrochloric acid gas. The insoluble aluminum chloride is then separated from the dissolved impurities and subjected to a second leaching step to solubilize and separate it from the silica gangue. Substantially pure AlCl.sub.3.sup.. 6H.sub.2 O crystals are recovered from solution and converted to alumina by conventional means. In an alternate embodiment, the process may be practiced on uncalcined clay and includes the addition of a source of fluoride ions, such as H.sub.2 SiF.sub.

Abstract: Organic and aqueous phases are separated from solvent extraction emulsions by treatment of the emulsions with diatomaceous earth at elevated temperature, whereby the emulsion-forming matter is sorbed by the diatomaceous earth.

Abstract: Improved efficiency of reverse-osmosis and ultrafiltration processes is achieved by backwashing membranes by means of electroosmosis. This is achieved by application of an electric potential across the membrane, thereby causing a backflow of water through the membrane.

Abstract: Separation of zirconium and hafnium by solvent extraction with a tertiary amine from sulfuric acid solution is improved by addition of water-soluble .alpha.-hydroxycarboxylic acid to the aqueous phase.